The present invention relates to a method and a device for controlling an internal combustion engine.
A method and device for controlling an internal combustion engine are described, for example, in German Published Patent Application No. 197 56 619. A system is described for operating an internal combustion engine, particularly in a motor vehicle, in which the air is supplied to a combustion chamber via a throttle valve arranged in an intake manifold, the quantity flow via the throttle valve being determined. At the same time, a valve is disposed in an exhaust-gas recirculation line, and the quantity flow via the valve in the exhaust-gas recirculation line is determined. The air-quantity flow into the combustion chamber is determined on the basis of the two air-quantity flows. A problem with this device is that different variables needed for the calculation can only be acquired with difficulty using sensors. Therefore, it is disadvantageous that a large number of sensors are necessary for detecting the different variables.
The procedure of the present invention makes it possible to determine the oxygen quantity flowing into the internal combustion engine. In so doing, only a few measured variables may be necessary which are easily detectable using simple, inexpensive sensors. Furthermore, variables are used which are present internally in the control unit for controlling the internal combustion engine. At least one speed variable (N), which characterizes the speed of the internal combustion engine, one charge-air temperature (T2), which characterizes the temperature in the intake manifold, and/or a charge-air pressure (P2), which characterizes the pressure in the intake manifold, is used as a measured variable.